Aerodynamic device



Q Oct. 5, 1943. R. K. ODOR ET AL 2,330,907

AERODYNAMIC DEVICE Filed Sept. 10, 1958 4Q Z 1g cz 3 9 8y ikeil' fibb 12936.

1 wa W Patented on5, 1943 UNITED STATES PATENT OFFICE AERODYNAMIO DEVICE Application September 10, 1938, Serial No. 229,378

11 Claims. (Cl. 230-114) The principal object of this invention is to provide a novel aerodynamic device, the aerodynamic properties of which may be of substantial utility in numerous practical" applications of the invention, as hereinafter set forth.

The invention is illustrated diagrammatically in the attached drawing, in which: Figure 1 is a sectional view of a preferred form of the device, taken on the line il in Fig. 2,

and

Fig. 2 is a front elevation of the device.

Referring to the drawing, the device in a preferred embodiment comprises a plurality of funnel-like tubes of differing effective diameters arranged coaxially and in telescoped relation, the larger end of each of the smaller tubes projecting from and extending beyond the corresponding end of the tube of next larger size.

Preferably the tubes are so relatively proportioned that the area of the inner or smaller end of each of the larger tubes is approximately twice that of the corresponding end of the next smaller tube. Thus, in the illustrated embodiment of our invention, the area of the smaller end la of the largest tube I, is approximately twice as great as that of the smaller end 2a of the second largest tube 2; and the area of the smaller end 3a. of the tube 3 is approximately'one-half that of the end 2a of the tube 2. Thus the area of the smaller end of each of the tubes I and 2 is approximately bisected by the smaller end of the tubes 2 and 3 respectively.

Preferably, also, the tubes are contoured and relatively proportioned as to length so that the gullets or spaces between the outer or larger ends of each adjoining pair of tubes are approximately of the same effective area and flow capacity. Thus, in the illustrated embodiment the gullet 4 between the larger ends of the tubes I and 2 is approximately the same in effective size as the gullet 5 between the larger ends of the tubes 2 and 3,

We have discovered that a tubular structure of this character possesses important aerodynamic properties. When placed, for example, in front of a rotating propeller or fan, as illustrated in Fig. 1, wherein the propeller is indicated by the reference letter P, it has the capacity to materially increase the efficiency of the propeller as expressed in terms of the quantity of air moved or circulated by the propeller for a given consumption of power. In actual test, for example, using common commercial types of propeller, the presence of the tube structure in front of the propeller resulted in increases in the amount of air moved of from 30% to 50%. In another test, using a commercial fan unit of highest available efiiciency, the presence of the tube structure increased the capacity of the unit to move air by as much as 75%. In a further comparative test it was found, that a fan unit made in accordance with our invention and utilizing a 14" propeller driven by a A; H. P. motor was capable of moving approximately the same quantity of air as a commercial unit of most eflicient available type employing a 27" propeller driven by a A H. P. motor. The propeller referred to is of the projected blade, screw type, i. e., a propeller or impeller having a. blade or blades projected from the hub or shaft in radial or other directions and not extending more than halfway around the shaft nor forming a section of a so-called "con- I tinuous screw.

In combination with'a propeller as described above, the tube structure exhibits other valuable characteristics. It permits safe operation of propellers at considerably higher speeds than has been possible heretofore, and without the sharply decreased efliciency which is characteristic of propellers operated above a given speed under conventional conditions. It also permits efficient operation of propellers of higher blade pitch; and materially reduces noise in operation.

As an aid to air movement, the utility of the device is not limited to propellers of the type shown, and is, in fact, independent of the mechanism or apparatus that may be employed to generate said air movement. It will, for example, when placed in advance of the intake opening of a centrifugal fan or blower, materially improve the efiiciency of that type of mechanism.

Another aerodynamic property of the device of considerable practical importance is the ability to generate thrust. Movement of air through the tube structure in the direction indicated by the arrows in Fig. 1 develops thrust in the opposite direction, the tube structure tending to move bodily in the axial direction against the airflow. This thrust is substantial and varies approximately in proportion to the amount of air moved. This characteristic of the device is of primary importance in the field ofaeronautics wherein the device may be used not only to increase propeller efiiciency, but also to create additional thrust.

It is to be understood that the invention is not limited to the specific embodiment illustrated in the drawing. In that embodiment, which is designed primarily for use in connection with commercial fan units, it was found desirable to locate the rear end of the tube 3 somewhat short of the corresponding ends of the tubes l and 2. Without departure from the invention, however, the tube 3 may be extended inwardly to a point adjoining the smaller ends of the other tubes. There may be considerable variation of this nature in the structure without departure from the invention. The number of tubes employed in the structure may also vary between wide limits,

and will depend in large degree upon the area of the smaller end of the largest tube. While two tubes arranged substantially in the relation of the tubes l and 2 in the illustrated embodiment have been found highly effective in certain applications of the invention, we prefer, where possible, to employ at least three tubes as illustrated. Furthermore, and as previously stated, the relative dimensions and arrangement of the tubes in the assembly and the forms and dimensions of the individual tubes are subject to considerable variation to meet the nature and special requirements of the individual application. Similarly, without departure from the invention, the axial contours of the tubes may vary considerably, within the general definition of funnel-like employed in the appended claims, it being noted that the consideration of axial contour is of particular significance in connection with the thrust factor. Similarly, the perimetral contour may be other than the cylindrical one illustrated, althoughthe cylindrical form is preferable. In general, however, it is believed desirable to so construct the tube assembly that the ratio of the effective areas at the front and rear respectively of each of the tubes shall be approximately the same; that is to say, with reference to the illustrated embodiment, the effective area of the gullet 4 shall have approximately the same ratio to the area of the annular space in between the smaller ends of the tubes l and 2, as does the gullet 5 to the space 5a, and the area of the larger end of the tube 3 to the area ofthe smaller end of that tube.

In some instances also it may be desirable, where available space is restricted, to dimension and arrange the tubes so that they terminate at their larger ends in, or substantially in, a common plane. While this expedient results in a somewhat reduced efliciency, it is to be noted that in this form the device retains in part the characteristics of the preferred embodiment described above, in that it affords in a unitary air-flow duct a plurality of longitudinally extending channels each of which, with reference to the direction of air flow, has a greater effective area at the intake end than at the discharge end. It is to be noted further that this relation of intake and discharge areas prevails even in those instances' where the radial space between the walls of the individual channel may be constant throughout the length of the channel, this by reason of the fact that the mean circumference of the channel in cross sectional area in one direction only from the larger toward the smaller end thereof, said tubesbeing nested for appreciable portions of their lengths one within another with the smaller end ofeach nested tube disposed in the same direction toward the discharge end of the duct,.

the larger ends of each successive inner tube being ef less diameter than the corresponding end of an adjacent outer tube and projecting beyond the larger end of said adjacent outer-tube and toward the intake end of the duct, the smaller end of the outermost tube of the assembly constituting the discharge end of said duct, said tubes being relatively dimensioned so as to afford between adjacent tubes longitudinally extending air flow channels each having an intake end independent of the intake ends of adjacent tubes; and a rotary projected blade, screw type propeller at the discharge end of the duct, which propeller, upon rotation, sets up a flow of air through the duct from the larger ends of all of said nested tubes to the smaller ends thereof, the collective area of the independent intake ends of the tubes being in excess of approximately two and onehalf times the area of the discharge end of the duct.

2. An aerodynamic device comprising in combination, an air-flow duct substantially free from obstruction and consisting of ,a plurality of tubes increases toward the intake end. It is to be noted, further, that without departing from the terms of certain of the appended claims defining the invention, one or more of the individual channels described above may be subdivided by longitudinally extending partitions. It is generally preferred, however, to maintain the channels in the circular or annular forms as illustrated.

While in the attached drawing we have illustrated the tube assembly diagrammatically, in the sense that no means is disclosed for securing the tubes together in their relative position, it will be understood that in a commercial unit some means, such as struts, or longitudinal partitions or vanes for connecting said tubes will be employed. a

We claim: Y

1. An aerodynamic device comprising in com bination, an air-flow duct substantially free from obstruction and consisting of a plurality of nested tubes each of funnel-like formation diminishing assembled in nested arrangement for appreciable portions of their lengths one within another, each of said tubes being of funnel-like formation having its least cross-sectional area at the terminal end thereof which is directed toward the discharge and of the duct and said tubes diminishing in said cross-sectional area solely toward said discharge end, said tubes'beingrelatively spaced one within another so as to divide the interior of the outermost tube of said duct into a plurality of longitudinally extending channels, the smaller end of the outermost tube of said assembly constituting the discharge end of said duct and the larger end of each successive inner tube being of less diameter than the corresponding end of an adjacent outer tube and projecting beyond the larger end of said adjacent outer tube and toward the intake end of the duct to constitute independent intakes for each of said longitudinally extending channels; and a rotary projected blade, screw type propeller at the smaller end of the outermost tube, which propeller, upon rotation, sets up a flow of air of non-diminishing velocity through all of the longitudinally extending channels from the larger ends of said tubes to the smaller ends thereof, the sum of the areas of the independent intake ends of said channels being in excess of approximately two and onehalf times the area of the discharge end of the outermost tube of the duct.

3. An aerodynamic device comprising in combination a duct consisting of a plurality of substantially unobstructed funnel-like tubes of circular cross-section assembled in spaced nested arrangement for appreciable portions of their lengths one within another about a common longitudinal axis, the smaller end of the outermost tube of said assembly constituting the discharge end of said duct and the larger end of each successive inner tube being of less diameter than the corresponding end of an adjacent outer tube and projecting beyond the larger end of said adjacent outer tube and toward the intake end of the duct to constitute independent intakes for the spaces between said tubes; and a rotary projected blade, screw type propeller at the smaller end of the outer tube, which propeller, upon rotation, sets up a flow of air of non-diminishing velocity through the duct from the larger ends of all of said nested tubes to the smaller ends thereof, each of said tubes having its least cross-sectional area at the, terminal end thereof which is directed toward the discharge end of the duct and each of said tubes diminishing in said cross-sectional area solely toward said discharge end, and said tubes being relatively spaced one within another so as to divide the interior of said duct into a plurality of substantially independent and substantially unobstructed coaxial air flow channels and said tubes being so proportioned that the sum of the areas of the independent intake ends of the channels shall be in excess of approximately two and one-half times the area of the discharge end of the duct.

4. .An aerodynamic device comprising in combination a substantially unobstructed air-flow duct comprising a plurality of nested funnel-like tubes of different diametrical size arranged coaxially in telescopic, spaced relation for appreciable portions of their lengths one within another with their larger ends disposed toward the intake end of the duct, each of said tubes having its least cross-sectional area at the terminal end thereof which is directed toward the discharge end of the duct and which tubes each diminish in said cross-sectional area solely toward said discharge end, the end of least cross-sectional area of the outermost tube of the assembly constituting the discharge end of said duct, the larger ends of the successively smaller tubes being of less diameter than the corresponding end of an adjacent outer tube and projecting from within and extending outwardly beyond thecorresponding end of said adjacent tube of greater size to form independent intakes for the spaces between adjacent tubes of the assembly, and the total effective intake area of the tubular assembly being in excess of approximately two and onehalf times the discharge area of the outermost tube of said assembly; and a rotary projected blade, screw type propeller at the discharge end of said duct, which propeller, upon rotation, sets up a flow of air through all of the spaces between the tubes from the intake to the discharge ends thereof.

5. An aerodynamic device as set forth in claim 4, wherein the ratio of the effective area at the intake and discharge ends respectively of each of the tubes is approximately equal.

6. An aerodynamic device comprising in combination an air-flow duct comprising a plurality of substantially unobstructed funnel-like tubes or different diametrical size arranged coaxially in spaced, substantially parallel telescopic relation for appreciable portions of their lengths one within another and each having its least crosssectional area at the terminal end thereof which is directed toward the discharge end of the duct and each of said tubes diminishing in said crosssectional area. solely toward said discharge end, the larger end of a lesser tube being of less diameter than the corresponding end of an adjacent outer tube of greater size and projecting from within and beyond the corresponding end of said adjacent tube of greater size, the end of least cross-sectional area of the outermost tube of the assembly constituting the discharge end of said duct, the total eflective intake area at the larger ends of the tubes being in excess of approximately two and one-half times the discharge area of the tube of greater size which constitutes the discharge end of said duct, and the end of least cross-sectional area of said lesser tube lying in proximity to the plane defined by the corresponding end of the adjacent tube of greater size; and a rotary projected blade, screw type propeller at the discharge end of the outermost tube of the assembly, which propeller, upon rotation, sets up a flow of air through all of the tubes constituting said air-flow duct from the intake to the discharge ends of said duct.

7. An aerodynamic device comprising in combination an air-flow duct substantially free from obstruction and comprising at least outer, intermediate and inner funnel-like tubes of progressively decreasing diametrical size arranged coaxially in telescopic, spaced and nested relation for appreciable portions of their lengths one within another with their larger ends constituting their intake ends and extending toward the intake end of the duct, the end of lesser diameter of each of said tubes constituting the discharge end thereof and being directed toward the discharge end of the duct and each of said tubes diminishing in diameter solely toward said discharge end, the intake end of the intermediate tube projecting from within and materially beyond the intake end of the outer tube and being of less diameter than the diameter of the corresponding end of said outer tube, the intake end of the inner tube projecting from within and materially beyond the intake end of the intermediate tube and being of less diameter than the diameter of the corresponding end of said intermediate tube, and the total effective area of the intake area between the outer and intermediate tubes, between the intermediate and inner tubes and the intake area of the inner tube being in excess of approximately two and one-half times the area/of the discharge end of the outer tube; and a rotary projected blade, screw type propeller at the discharge end of the outer tube, which propeller, upon rotation, sets up a flow of air through the duct from the intake areas of the outer, intermediate and inner tubes to the discharge ends thereof.

8. An aerodynamic device as set forth in claim '7 wherein the ratio of the effective areas at the intake and discharge ends respectively of each of the outer, intermediate and inner tubes is approximately equal, and wherein further the area of the discharge end of the intermediate tube is approximately one-half the area of the discharge end of the outer tube.

9. An aerodynamic device as set forth in claim 7 wherein the discharge end of the inner tube is spaced from the discharge end of the intermediate tube in the direction of the intake end of the duct.

10. An aerodynamic device as set forth in claim 7 wherein the ratio of the effective areas at the intake and discharge ends respectively of each of the outer, intermediate and inner tubes is approximately equal, and wherein further the area of the discharge end of the inner tube is approximately one-half the area of the discharge .end of the intermediate tube.

' 11. An aerodynamic device as set forthin claim 7 wherein the discharge end of the intermediate tube is spaced from the discharge-end of the outer tube in the direction of the. intake end of the duct.

RALPH K. ODOR. KERN DODGE. 

